Sealing apparatus for rotary mechanism



Nov. 25, 1.969 KOCH 3,480,203

SEALING APPARATUS FOR ROTARY MECHANISM Filed Jan. 29, 1968 INVENTOR.

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United States Patent 3,480,203 SEALING APPARATUS OR ROTARY MECHANISM David A. Koch, Southfield, Mich., assignor to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Filed Jan. 29, 1968, Ser. No. 701,358 Int. Cl. F04c 27/00; F01c 19/04 US. Cl. 230-145 5 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to rotary mechanisms, and more particular to sealing apparatus for a rotary compressor.

There are several types of rotary compressors and the present invention is described in connection with, although it is not limited to, a rotary compressor of the type comprising an outer body having an axis, side walls axially spaced from one another, and a peripheral wall interconnecting the side walls. The inner surface of the peripheral wall and the side walls form a cavity within which an inner body or rotor is mounted. The inner surface of the peripheral wall is substantially parallel to the axis of the cavity and the cross section of the cavity is generally similar to a conchoid of a circle having a chord approximately equivalent to the length of the rotor. The axis of the rotor is parallel to the axis ofthe outer body cavity and the rotor has side faces adjacent the side walls of the body. The rotor has two cir-cumferentially spaced apex portions and in side elevation resembles the profile of a football.

The rotor is rotatable relative to the outer body in such a manner that the apex portions continuously engage the inner surface of the peripheral wall to form two working chambers between the rotor peripheral surface and the inner surface of peripheral wall of the outer body. These chambers vary in volume during compressor operation as a result of the relative rotation of the rotor and outer body. Rotary compressors of this type include at least one intake or suction port or passage in the outer body for admitting gas, such as refrigerant, to the compressor, and a discharge port or passage in the outer body for discharging compressed gas from the compressor.

The working chambers of the compressor, for eflicient operation of the latter, should be substantially sealed against leakage, although the seal does not have to be as effective as would be required if the mechanism were utilized in rotary combustion engine apparatus since the latter are driving apparatus and must generate pressure for starting while compressors are driven, rather than driving apparatus.

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In regard to the sealing apparatus, it is necessary to provide a seal between each rotor apex portion and the inner surface of the peripheral wall of the outer body, as well as between the side faces of the rotor and the side walls of the body to seal against substantial leakage from the high prsesure or discharge side of the rotor to the low pressure or suction side of the rotor. This invention relates to such sealing apparatus for providing a seal between each rotor apex portion and the inner surface of the peripheral wall of the outer body and the outer portion of the side walls of the body.

BRIEF SUMMARY OF THE INVENTION Briefly, this invention comprises a rotary compressor having two apex sealing plates at each apex of the compressor rotor, and sealing pins at the radially inner ends of the sealing plates, means biasing all of the sealing members axially outwardly against side walls of the compressor, the apex sealing plates and sealing pins being located relative to one another and to the rotor so as to permit compressed fluid to aid in the biasing of the sealing members by the aforementioned means.

One of the primary objects of this invention is to provide apex sealing apparatus for the rotor of a rotary compressor, the apparatus being adapted substantially to seal the space between the apex portions of the rotor and Walls of the cavity in which the rotor rotates.

Another object of this invention is to provide sealing apparatus of the class described in which the gas being compressed is utilized to increase the effectiveness of the seal against leakage of the gas.

A further object of this invention is to provide sealing apparatus such as described in which the apex seals are substantially prevented from becoming improperly aligned during operation.

Still another object of this invention is to provide sealing apparatus of the type described wherein the corners of each apex of the rotor are effectively sealed against the walls of the cavity of the outer body without complex interleaved sealing pieces.

Another object of this invention is to provide sealing apparatus of the class described which is economical in construction and effective in operation.

Other objects and advantages of the invention will be made apparent as the description progresses.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, in which one of various possible embodiments of this invention is illustrated,

FIG. 1 is a side elevation of a rotary compressor con structed in accordance with this invention, certain parts being broken away and removed for clarity;

FIG. 2 is an enlarged fragmentary view of FIG. 1; and

FIG. 3 is a section taken along line 33 of FIG. 2.

Like parts are indicated by corresponding reference characters throughout the several views of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, a rotary mechanism of this invention in the form of a rotary compressor is generally indicated at 1. Basically, it comprises an outer fixed body 3, and an inner body or rotor 5. The rotor 5 is provided with apex sealing apparatus at each apex of the rotor as indicated at 7.

More specifically, the outer body 3 has axially spaced side walls 11 and 13 and a peripheral wall 15 disposed therebetween to form a cavity 17. Only one cavity 17 is shown in the body 3 illustrated herein, but it will be understood that the compressor may be constructed with a plurality of cavities 17 therein located side-by-side, if desired. When the compressor is viewed in a plane extending transversely to an axis 19 of the cavity 17, the inner surface 21 of the peripheral wall 15 has a profile which closely approximates a conchoid of a circle having a chord approximately equivalent to the length of the rotor.

An inlet or suction port 23 is provided in Wall 15. Port 23 places a cavity 25, which is adapted to be connected to a suction line of a refrigeration system (not shown), in communication with the cavity 17. An outlet or discharge port 27 is also formed in wall 15 at a point circumferentially displaced from suction port 23. Port 27 is adapted to place cavity 17 in communcation with a cavity or passage 29 in wall 15. Port 27 is normally closed by a valve, such as a reed valve 31, which valve is adapted to open upon the existence of a predetermined pressure in port 27. Passage 29 is adapted to be connected to a discharge line (not shown) of refrigeration system by a port 33.

Rotor 5 has a cylindrical recess or opening 34 therein in which a ring gear (not shown) having internal teeth (not shown) is securely seated and connected to the rotor. As will be understood, the ring gear teethare adapted to roll on a gear (not shown) fixed to the wall 13 of body 3. The rotor 5 is adapted to be given a uniform movement of rotation by a crankshaft (not shown) which carries an eccentric (not shown) adapted to engage a bearing surface 39 (FIG. 3), The driving mechanism including the fixed gear, the shaft and the eccentric are well-known and a detailed description thereof is superfluous to the description of this invention. Sufiice to say that the'driving mechanism may be similar to the apparatus shown in US. Patent 1,636,486 issued July 19, 1927 to B. R. Planche. Each apex of the rotor 5 has a radially extending generally U-shaped slot 41 therein at the radially inner ends of which there is formed a cylindrical bore 43 extending transversely and axially of the rotor. The bore forms holes in opposite sides of the rotor. A web 45 forms the U-shape of the slot and is located radially outward of the bore 43.

The apex sealing apparatus 7 at each apex portion of the rotor 5 includes two generally L-shaped sealing plates or members 47 and 49 slideably received in slot 41. The plates 47 and 49, respectively, have axially extending portions or legs 51 and 53 and radially extending legs or portions 55 and 57. The radially outer edges of legs 51 and 53 are adapted to contact the inner surface 21 of wall 15 while the axially outer edges of legs 55 and 57 are adapted to contact side walls 11 and 13, respectively.

The radially inward end portion of legs 55 and 57 are provided with curved seats 59 and 61, respectively, on the axially inner side thereof against one of which one curved end 63 of a spreader and stabilizing spring 65 seats. Spring 65 is a compression spring formed of three legs 67, 69 and 71. Leg 67 is bowed and contacts the axially inner edge of sealing plate 47 at seat 59 and adjacent the juncture of plate legs 51 and 55. Leg 69 is generally straight and extends over web 45 to leg 71. The latter leg is bowed and shorter than leg 67 and has a curved end 73 which engages the inner edge of the leg 57 of sealing plate 49. The spring 65 biases the sealing plates 47 and 49 apart against the body side walls 11 and 13. The spring 65 contacts the plates 47 and 49 at three points. This three point contact effectively prevents canting or movement of one plate relative to the other such as might occur if the spring engaged the plates at two or four points, for example. The axially inner ends of legs 51 and 53 are spaced from one another as indicated at 75, which as pointed out hereinafter provides a passage through which a small amount of gas under high pressure may pass from the high pressure side of the cavity 17 to the space between the sealing plates 47 and 49 for increasing the outwardly directed force on the sealing plates.

The radial inner ends of legs 55 and 57 extend radially inward beyond the radially inner ends of slot 41 into grooves 77 and 79 extending in an axial direction in cylindrical seal pins 81 and 83 located in bore 43. The axially inner ends of pins 81 and 83 are of reduced diameter so as to form shoulders 85 and 87, respectively, thereon. A compression spring 89 surrounds the reduced diameter ends of the pins and engages the shoulders 85 and 87 to bias the pins axially outward away from one another. The depth of grooves 77 and 79 is sufficient to permit radial movement of the plates 47 and 49 therein. However, as will be made apparent hereinafter, the depth of the grooves is not sufficient to permit the plates 47 and 49 to be moved completely out of the groove in a radial direction when the rotor 5 is in cavity 17.

It will be understood that suitable sealing apparatus (not shown) is provided on the sides of the rotor to block communication between the cavity 17 and the opening or recess in the center of the rotor and to block'communication across the radially inner portions of the pins 81 and 83.

Assuming the rotor 5 is in the position shown in FIG. 1 and is rotating in a clockwise direction as viewed in FIG. 1, operation of the sealing apparatus is as follows:

Gas, such as refrigerant vapor, has been forced through port 23 into cavity 17 and is dispersed in the cavity on the right-hand side of rotor 5, as viewed in FIG. 1. The refrigerant previously forced into the cavity when the rotor was in a position which precedes the FIG. 1 position by degrees, has been compressed to the volume shown on the left-hand side of the rotor as viewed in FIG, 1. It will be seen that as the rotor 5 rotates the sealing plates 47 and 49 of each apex sealing structure 7 are thrown radially outwardly against the inner surface 21 of peripheral wall 15 to seal against refrigerant leakage, except through the space between the radially outer edges and axially inner ends of the plates 47 and 49. When the pressure of the refrigerant being compressed slightly exceeds the pressure of the refrigerant in the discharge line 33, reed valve 31 is forced open and the compressed refrigerant begins to discharge from cavity 17 into the discharge line. However, prior to being discharged and during discharge the refrigerant which has been compressed exerts a high pressure on the sealing structure 7. In this regard, the refrigerant pressure is exerted on the seals generally in the direction of the arrows A in FIGS. 1 and 2.

The thickness of slot 41 is sufficient to permit a slight movement of the plates 47 and 49 against the side thereof away from the compressed refrigerant and away from the side of the slot adjacent the compressed refrigerant, thereby permitting the compressed refrigerant to pass radially inwardly across the faces of the plates 47 and 49 to the space therebetween. A very small portion of the refrigerant under a high pressure also passes into the space between the axially inner ends of the legs 51 and 53 of sealing plates 47 and 49. A small portion of this refrigerant will, of course, escape to the suction side of the rotor 5 through the portion of the space between the inner surface 21 of wall 15 and the outer edges of the apex portions of the rotor. However, the small amount of high pressurized refrigerant referred to above also passes through space 75 into the space between web 45, plates 47 and 49 and sealing pins 81 and 83. Thus refrigerant under a high pressure passes both across the faces of plates 47 and 49 and through space 75 to the space around web 45. The refrigerant between the axially extending inner surfaces of plates 47 and 49 and the axially extending outer surfaces of web 45 and pins 81 and 83 tend to force the plates radially outwardly against the inner periphery 21 of wall 15. Similarly, the refrigerant between the radially extending inner surfaces of the plates 47 and 49 and the radially extending surfaces of web 45 tend to force the plates 47 and 49 axially outwardly against the side walls 11 and 13. Moreover, the refrigerant between the sealing pins 81 and 83 tends to force them axially outwardly against the side walls. Thus, the highly pressurized refrigerant aids the spring 65 and 89 and the radially outward force on plates 47 and 49 in maintaining the plates against the surface 15 and walls 11 and 13.

It will be understood that as the refrigerant on the discharge side of the rotor is being compressed, additional refrigerant vapor is being delivered through port 23 to the suction side of the rotor. After the compressed refrigerant is discharged the newly admitted refrigerant on the suction side of the rotor will be compressed due to the continuous movement of the rotor in the body 3.

It will be seen that the apex sealing structure is constructed to utilize the refrigerant being compressed for increasing the effectiveness of the seal provided by such structure.

In view of the foregoing, the various objects and other advantages of this invention are obtained.

it will be understood that the invention is not to be limited to the exact constructions shown and described, but that various changes and modifications may be made without departing from the spirit and scope of the invention.

I claim:

1. A rotary mechanism comprising a body formed of axially spaced side walls and a peripheral wall connecting said side walls to form a cavity therebetween, a rotatable rotor in the cavity having a plurality of apex portions movable generally along the peripheral wall as the rotor rotates, and means for sealing against substantial communication between the portions of said cavity adjacent opposite peripheral sides of each apex of said rotor, said apex portions having generally radially extending slots therein and generally axially extending holes extending inwardly from opposite sides of said rotor at the radially inward ends of said slot, said means comprising a pair of generally L-shaped apex sealing members in each slot movable radially therein, each of said generally L-shaped sealing members having an axially extending leg and a radially extending leg, the combined length of said axially extending legs being approximately equal to but slightly less than the distance between said side Walls, means biasing the apex sealing members in each slot axially outward away from one another and against said side walls, the radially outer and axially inward ends of said axially extending legs of said apex sealing members in each of said slots being axially spaced from one another, sealing pins in said holes, said sealing pins having slots in the radially outer portions thereof into which the axially outer portions of the radially inner ends of said radially extending legs of said apex sealing members extend, and means biasing said sealing pins axially outward against said side walls.

2. A rotary compressor comprising a body formed of axially spaced side walls and a peripheral wall connecting said side walls to form a cavity therebetween, an inlet port for admitting fiuid to be compressed to said cavity, an outlet for discharging compressed fluid from said cavity, a rotatable rotor in the cavity having a plurality of apex portions movable generally along the peripheral wall as the rotor rotates to compress fluid admitted to the cavity, means for sealing against substantial communication between the portions of said cavity on opposite peripheral sides of each apex of said rotor to prevent substantial transfer of fluid from one peripheral side of the rotor adjacent each apex portion to the other peripheral side of the rotor adjacent the same apex portion, said apex portions having generally radially extending slots therein and generally axially extending holes extending inwardly from opposite lateral sides of said rotor at the radially inward ends of said slot, said means comprising a pair of apex sealing members in each slot movable radially rand axially therein, means biasing the apex sealing members in each slot axially outward away from one another and against said side walls, the axially inward ends of said apex sealing member in each of said slots being axially spaced from one another to provide a passage therebetween, sealing pins in said holes, said sealing pins having slots in the radially outer portions thereof into which the axially outer portions of the radially inner ends of said apex sealing members extend, and means biasing said sealing pins axially outward against said side walls to substantially seal one peripheral side of said rotor adjacent each apex portion from the other peripheral side of said rotor adjacent the same apex portion, said means biasing the apex sealing members away from one another comprising a spring extending therebetween, said spring contacting one of said apex sealing members at two points and contacting the other apex sealing member at one point to provide a stabilizing bias on the apex sealing members.

3. A rotary compressor as set forth in claim 2 wherein the radially inner ends of said apex sealing members are spaced outwardly from the bottoms of slots in the radially outer portions of said sealing pins when said rotor is rotating, said apex sealing members being thinner than said slots to permit compressed fluid to pass between said apex sealing members and the walls of said slots to force said apex sealing members radially and axially outwardly.

4. A rotary mechanism comprising a body formed of axially spaced side walls and a peripheral wall connecting said side walls to form a cavity therebetween, a rotatable rotor in the cavity having a plurality of apex portions movable generally along the peripheral wall as the rotor rotates, and means for sealing against substantial communication between the portions of said cavity adjacent opposite peripheral sides of each apex of said rotor, said apex portions having generally radially extending slots therein and generally axially extending holes extending inwardly from opposite sides of said rotor at the radially inward ends of said slot, said means comprising a pair of apex sealing members in r each slot movable radially therein, means biasing the apex sealing members in each slot axially outward away from one another and against said side walls, the radially outer and axially inward ends of said apex sealing members in each of said slots being axially spaced from one another, sealing pins in said holes, said sealing pins having slots in the radially outer portions thereof into which the axially outer portions of the radially inner ends of said apex sealing members extend, and means biasing said sealing pins axially outward against said side walls, said means biasing the apex sealing members away from one another comprising a spring extending therebetween, said spring contacting one of said apex sealing members at two points and contacting the other apex sealing member at one point to provide a stabilizing bias on the apex sealing members.

5. A rotary compressor comprising a hollow housing, a rotor having a plurality of apex portions rotatable in said housing, two radially extending apex sealing plates at each apex of the said rotor, each of said sealing plates being generally L-shaped and having an axially extending leg and a radially extending leg, the combined length of said axially extending legs being approximately equal to the width of said rotor, sealing means at the radially inner ends of the sealing plates, said sealing means having slots therein into which the inner ends of said radially extending legs extend, means biasing the sealing plates and sealing means outwardly against the walls of the housing, the apex sealing plates and sealing means being located relative to one another and to the rotor in a manner to permit the fluid being compressed 7 8 to aid said means in biasing the plates, and sealing 3,300,127 1/1967 Yamamoto et a1. 230-145 means outwardly against said housing Walls. 3,301,231 1/1967 Tado. 3,359,951 12/1967 Sabet. References Cited 3,400,691 9/1968 Jones 230-145 X UNITED STATES PATENTS r DO LE KIN 5/1965 Hanns-Dieter Paschke 0 N Y J STOC G Pnmary Exammer 230-152 X 7/1965 Bentele' WARREN J. KRAUSS, Asslstant Exammer 7/1965 Hanns-Dieter Paschke 123-8 U.S. Cl. X.R.

Hanns-Dieter Paschke 10 

